Pronunciation: (out"sī'dur),[key] —n. 1. a person not belonging to a particular group, set, party, etc.: Society often regards the artist as an outsider. 2. a person unconnected or unacquainted with the matter in question: Not being a parent, I was regarded as an outsider. 3. a racehorse, sports team, or other competitor not considered likely to win or succeed.
4. a person or thing not within an enclosure, boundary, etc.